Electrodes Based on Inorganic Salts of Transition Metals

1 ELECTRODES BASED ON INORGANIC SALTS OF TRANSITION METALS 

Electrochemical Power Sources Batteries, Fuel Cells, and Supercapacitors, First Edition. Vladimir S. Bagotsky, Alexander M. Skundin, and Yurij M. Volfkovich 2015 John Wiley Sons, Inc. Published 2015 by John Wiley Sons, Inc. 

The main difference between PsC and electric double-layer capacitor (EDLC) is that there is no overall ion exchange between the electrode and electrolyte in PsCs. That is, the concentration of electrolyte remains constant during the charging and discharge. As pointed out above, EDL capacitance in such systems always coexists with pseudocapacitance. However, the amount of ions participating in the process of EDL formation is much lower than the amount of protons exchanged between the two electrodes. Thus, pseudocapacitance is much higher than EDL capacitance in the same system. 

In the work of Yue-feng et al. (2007) were measured three galvanostatic curves for three positive electrodes containing various amounts of Ru. Capacitance of PsCs grows at an increase in the content of ruthenium. Besides, these curves are close to straight lines and this confirms that electrodes with ruthenium oxides feature capacitive behavior described by Conway (1999) (see above). 

Though capacitance of the electrodes and the active materials obviously increased at an increase in the Ru content in electrodes, specific capacitance contributed by RUO2 H2O herewith decreases. For example, this value is 701.7 F/g for 2% Ru and 434.5 F/g for 30% Ru. Close results were obtained for the system of RUO2/AC in H2SO4 in electrolyte. 

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